Landsat 8 views from space of the 3 lakes at the summit of the Kelimutu volcano in Indonesia, known to change color unpredictably, via NASA Earth Observatory.

This composite image of Kelimutu volcano in Indonesia was the NASA Earth Observatory Image of the Day for July 6, 2018. It called them volcanic mood rings and explained:

Turquoise - Blood - Lakes - Summit - Kelimutu

From milky white to vibrant turquoise to blood red, the three lakes at the summit of the Kelimutu volcano are known to unpredictably change color— a phenomenon unique to this volcano on the Indonesian island of Flores.

These images, acquired by the Operational Land Imager on Landsat 8, show the various colors of the crater lakes on three different days. All three crater lakes appear on the crest of the volcano with the eastern two lakes sharing a common crater wall … Depending on when you visit, the colors can range from white, green, blue, brown, or black. In 2016, the lakes changed colors six times.